Linear actuator assembly

ABSTRACT

A linear actuator assembly including an axially moveable threaded shaft disposed within a rotationally driven housing which guides axial movement of the threaded shaft. A pair of oppositely disposed centrifugal members are pivotally mounted on the rotated member for movement from one engaged position with the threaded shaft through a disengaged position, where the shaft is free to move axially, to an opposite engaged position. The centrifugal members each have spaced half nuts and one pair of half nuts engage the threaded shaft upon rotation of the housing in one direction to move the shaft axially in the first direction and the other half nuts threadedly engage the shaft and move the shaft in the opposite direction upon rotation of the housing in the opposite direction. The limits of the threaded portion of the shaft are defined by lengths of reduced cross section. These lengths of reduced cross section limit the axial movement of the shaft as the half nuts disengage the threaded portion of the shaft by moving axially into one of the lengths of reduced cross section.

United States Patent 11 1 Tucker [54] LINEAR ACTUATOR ASSEMBLY Thomas M. Tucker, Royal Oak, Mich.

[73] Assignee: McCord,

Mich.

[22] Filed: Aug. 16, 1971 [2i] Appl. N0.: 171,932

[75] Inventor:

Corporation, Detroit,

[52] [1.8. CI ..74/89.l5, 74/424.8 A, 74/625, 192/105 C [51] Int. Cl ..Fl6|'l 29/20 Field of 89 R, 103, 105 74/105 CS, 424.8 A, 625; 137,4 9, 53;

Primary Examiner-Robert L. Wolfe Assistant Exqminer-Lawrence .I. Staab Attorney-McGlynn, Rusing, Milton & Ethington 57 V ABSTRACT A linear actuator assembly including an axially moveable threaded shaft disposed within a rotationally driven housing which guides axial movement of the threaded shaft. A pair of oppositely disposed centrifugal members are pivotally mounted on the rotated member for movement from one engaged position with the threaded shaft through a disengaged position, where the shaft is free to move axially, to an opposite engaged position. The centrifugal members each have spaced half nuts and one pair of half nuts engage the threaded shaft upon rotation of the housing in one direction to move the shaft axially in the first direction and the other half nuts threadedly engage the shaft and move the shaft in the opposite direction upon rotation of the housing in the opposite direction. The limits of the threaded portion of the shaft are defined by lengths of reduced cross section. These lengths of reduced cross section limit the axial movement of the shaft as the half nuts disengage the threaded portion of the shaft by moving axially into one of the lengths of reduced cross section.

12 Claims, 5 Drawing Figures PATENTEDJMI 16 ms 3.710.632

sum 2 OF 2 Egg? E22 TTORNEYS 2 w m 8 5 a w w a w m V a w m f 1 v iii vvvl 212 m $022205 HZ JzcKer LINEAR ACTUATOR ASSEMBLY This invention relates to a linear actuator assembly and more specifically to such an assembly which has particular utility in an automobile door locking system.

Automobile doors are locked by pushing a button, which is located on the windowsill, downwardly to prevent the automotive door from being opened from the exterior. A recent innovation utilized with such door locking assemblies is a single switch on the dashboard of the automobile which may be actuated to simultaneously lock or unlock all of the doors in the vehicle by moving the buttons associated with the various doors in unison. One of the requirements of any system wherein the doorlock buttons may be simultaneously moved between locked and unlocked positions is that the door buttons may be individually manually moveable independently of other components of the system.

One such prior art assembly is disclosed and claimed in dominant patent application Ser. No. 887,168 filed Dec. 22, 1969, now abandoned and continuation application Ser. No. I 1 3,222 in the name of Willis L. Kibler and assigned to the assignee of the instant invention. In that prior art assembly an axially moveable threaded shaft is disposed within a rotatable member. One end of the shaft defines the locking button and the shaft is connected to the locking mechanism for the door of an automobile. A pair of centrifugally actuated members are pivotally connected to the rotatable housing for pivotal movement about an axis transverse to the axis of the shaft. The lower ends of the centrifugal members are weighted and the upper ends define half nuts engageable with the threaded shaft. Thus upon rotation of the housing, and consequently the cylindrical members, in either direction the weights move outwardly to move the half nuts into threaded engagement with the shaft and depending upon the direction of rotation the shaft moves axially up or down. The axial movement of the shaft is limited in that the shaft includes lengths of reduced cross section at either end of a threaded portion whereby the half nuts move out of threaded engagement with the threaded portion of the shaft by being disposed in one of the lengths of reduced cross section. Once the threaded shaft has moved axially so that the half nuts are disposed in one of the lengths of reduced cross section, rotation of the housing is discontinued and the threaded'half nuts move away from the shafL'In order to move the shaft axially in the opposite direction, however, it is necessary to bias the shaft and the half nuts axially relative to one another so that when the centrifugal members move outwardly to move the threads into engagement with the shaft, the threads grab or bite upon the threaded portion of the shaft. In other words, the threaded half nuts are biased into engagement with the threaded portion of the shaft to assure threaded engagement upon rotation of the half nuts about the shaft.

The disadvantage'of this prior art assembly is that due to the biasing action urging the threaded shaft axially to engage the half nuts, noises are generated when the shaft is moved axially to the position where the half nuts are disposed in the lengths of reduced cross section and there is continued rotation of the housing and centrifugal members. In other words, the springs or other mechanical devices used to urge the return of the half nuts onto the threaded portion of the shaft while the motor is still running cause noise and vibration problems.

Accordingly, it is an object and feature of this invention to provide an improved linear actuator assembly which overcomes problems associated with prior art assemblies.

In correlation with the foregoing object and feature, it is another object and feature of this invention to provide a linear actuator assembly including an axially moveable threaded member disposed within a rotatable member rotatable about the axis of the threaded member and centrifugally actuated means movably supported on the rotated member for movement from a first engaged position in response to rotation in one direction through a disengaged position to a second engaged position in response to rotation in the opposite direction with the centrifugal means including first thread means for engaging the threaded member in the first engaged position to move the threaded member axially in one direction and second thread means for engaging the threaded member in the second engaged position to move the threaded member in the opposite direction with the first and second thread means being alternatively engageable with the threaded member.

In correlation with the foregoing objects and features, it is another object and feature of this invention to provide such an assembly wherein the threaded member comprises a shaft with a threaded portion and a length of reduced cross section at each end of the threaded portion for limiting axial movement of the shaft as the first and second thread means disengage the threaded portion by moving axially into the lengths of reduced cross section.

In correlation with the foregoing objects and features, there is another object and feature of this invention to provide such an assembly wherein the first and second thread means are spaced from one another axially of the shaft so that when one of the thread means is positioned to be disposed in one of the lengths of reduced cross section the other thread means is positioned to engage the threaded portion, and vice versa.

Other objects and attendant advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

FIG. 1 is a fragmentary perspective view of an au tomobile body showing the instant invention utilized inthe door latch mechanism;

FIG. 2 is a fragmentary cross sectional view of a preferred embodiment of the instant invention shown in the disengaged position where the shaft may be moved manually so as to manually position the lock button;

FIG. 3 is a cross sectional view taken substantially along line 3-3 of FIG. 2;

FIG. 4 is a view similar to FIG. 2 showing the assembly in one of the engaged positions for moving the shaft'axially;

FIG. 5 is a cross sectional view taken substantially along line 55 of FIG. 2.

Referring to the drawings, FIG. 1 discloses an au tomotive door assembly 10. Door assembly 10 includes the well known lock button 12 which is pushed downwardly for locking the door and is raised upwardly for unlocking the door. The locking button 12 is integral with or is attached to and disposed at the upper end of a shaft 14. The shaft 14 is connected through the lever 16 and rod 18 to a door latching or locking mechanism which is in turn biased, as by an over center spring, to the locked or unlocked position whereby the shaft 14 and the button 12 are maintained in the locked and unlocked positions respectively when moved thereto. A more detailed description and understanding of such a latch mechanism, to which the rod 18 may be attached, is disclosed in US. Pat. No. 3,423,l 17.

A linear actuator assembly constructed in accordance with the instant invention is generally shown at 20. The actuator-assembly is driven by an electric motor 22, the latter having a drive shaft 24 extending therefrom.

The linear actuator assembly includes an axially moveable threaded member which is defined by the elongated shaft 14. The shaft 14 includes a threaded portion 26 with lengths of reduced cross section 28 and 30 at each end of the threaded portion 26.

The assembly also includes a rotated or drive member or housing 32 which is rotatable about the axis of the shaft 14. The housing 32 has a splined connection 34 with the motor shaft 24 so as to be rotated thereby. The rotated member or housing 32 guides the axial movement of the shaft 26 and includes flanges 36 at its upper end for coaction with the springs 38, the purpose of which will become more clear hereinafter. The shaft 14, which is integral with or rotatably attached to the bottom of the lock button 12, is prevented from rotating by its connection to the lever 16. It will be understood that other suitable means may be utilized to prevent the shaft 14 from rotating within the housing 32.

The actuator assembly 20 also includes centrifugally actuated means moveably supported on the rotated housing member 32 for movement from a first engaged position (as illustrated in FIG. 4) in response to rotation in one direction through a disengaged position (shown in FIG. 2) to a second engaged position (not shown) in response to rotation in the opposite direction. The centrifugal means includes first thread means, comprising the half or split nuts 44, for engaging the threaded shaft 14 in the first engaged position, as shown in FIG. 4, to move the shaft 14 axially in one direction, i.e., downwardly. The centrifugal means also includes second thread means including the half or split nuts 46 for engaging the threaded shaft 14 in the second engaged position (not shown) to move the threaded member or shaft 14 in the opposite upward direction, the split nuts 44 and 46 being alternatively engageable with threaded shaft 14.

The centrifugal means includes centrifugal members 48 and 50. Each centrifugal member is connected to the rotated housing member 32 by pins 52 for pivotal movement about a pivotal axis (the axis of the pins 52) which is transverse to the shaft 14.

The centrifugal member 48 defines a V-shaped support platform 54 and the centrifugal member 50 defines a similar V-shaped support platform 56. One side of the centrifugal member 48 extends downwardly to define the depending leg 58 which is disposed on one side of the support housing 32 and includes the boomerang shaped car 60 disposed on the opposite side of the housing 32. In the same manner but in reversed positions the centrifugal member 50 has a depending leg 62 on one side of the housing 32 and a boomerangshaped ear 64 on the opposite side of the housing 32. The legs 58 and 62 are disposed opposite to one another and boomerang-shaped flanges 60 and 64 are disposed opposite to one another.

The depending legs 58' and 62 have weights 66 disposed at the bottoms thereof. Flanges 68 extend along the legs 58 and 62. Each centrifugal member also has an upwardly extending projection 70 which is attached to a spring 38. The springs 38 define biasing means biasing the centrifugal members 48 and 50 to the disengaged position shown in H0. 2.

Each half or split nut 44 is supported by the V- shaped platform of each centrifugal member axially of the shaft 14 on one side of the pivotal axis of the pins 52, i.e., upwardly of the pivotal axis defined by the pin 52, and the half nuts 46 are supported by the centrifugal members axially downwardly of the shaft 14 on the other side of the pivotal axis defined by the pins 52. In other words, the half or split nuts 44 are disposed upwardly of the pins 52 whereas thehalf or split nuts 46 are disposed downwardly of the pins 52. The V-shaped supporting platform of the centrifugal members 48 and 50 allow both pairs of half nuts 44 and 46 to be spaced from the shaft 14 when in the disengaged position illustrated in FIG. 2. The disengaged position is one wherein the motor 22 is not rotating and the shaft 14 is free to move axially up and down within the housing 32. The housing 32 has an opening extending therethrough and the half nuts 44 and 46 move into the opening 53 to engage the shaft 14.

Each of the centrifugal members, as mentioned above, include the weights 66 at the lower ends thereof with the weights being disposed alongside of and on opposite sides of the housing 32. The weights 66 are disposed alongside of the shaft 14 and alongside of the rotated housing member 32 when in the disengaged position illustrated in FIG. 2.

The centrifugal members 48 and 50 are substantially similar to one another but are oppositely disposed with the second centrifugal member 50 having its weight 66 disposed on the opposite side of the shaft 14 from the weight 66 of the first centrifugal member 48. The half nuts or split nuts 44, which define first thread means, engage opposite sides of the threaded portion 26 of the shaft 14 when in the first engaged position illustrated in FIG. 4 to move the shaft 14 axially downwardly. In a similar manner, although not shown, the half or split nuts 46 may be moved from the position shown in FIG. 2 into engagement with opposite sides of the threaded portion 26 of the shaft 14 in a second engaged position to move the shaft 14 axially upwardly.

The pair of half nuts 44 are spaced axially along the shaft 14 from the pair of half nuts 46 so that when the half nuts of one pair are positioned to be disposed in one of the lengths 28 or 30 of reduced cross section the other pair of half nuts is positioned to engage the threaded portion 26, and vice versa.

The assembly is shown in FIG. 2 at the at rest or disengaged position where the shaft 14 may be freely moved axially independently of actuation of the motor 22. lf it is desired to actuate all of the door lock mechanisms in an automobile a master switch isthrown to energize the motor 22 to affect its rotation to-rotate the output shaft 24. In the position illustrated in FIG. 2, the shaft 14 is at its lower position where the .door locking mechanism is in the locked position. Upon rotating the rotated housing member 32 in the clockwise direction as viewed in FIG. 3, the weights 66 effect pivotal movement of the centrifugal members 48 and 50 so as to engage the half or split nuts 46 with the threaded portion 26 of the shaft 14. In this engaged position of the split or half nuts 46 with the shaft 14, rotation of the half or split nuts 46 about the shaft 14 causes the shaft 14 to move upwardly. The shaft 14 continues to move upwardly as the motor 22 continues to run. Eventually the shaft 14 will be moved upwardly sufficiently that the half or split nuts 46 will move into the lower recess or reduced cross section 30 and out of engagement with the threaded portion 26. In this position the threads 26 of the shaft 14 may be completely out of engagement with the half or split nuts 46 to alleviate any noise problem. This is accomplished as the shaft 14 is biased to its upward and lowered positions respectively by an over center spring. in the locking mechanism so that the'last degree of upward movement of the shaft 14 clearly separates the threads 26 from the half or split nuts 46. Upon discontinued rotation of the motor 22, the assembly will return to the disengaged position.

To return the shaft 14, from its raised or unlocked position back downwardly to the locked position, the motor 22 is rotatedin the opposite or counterclockwise direction to move the centrifugal members 48 and 50 to the position shown in FIG. 4 where the half or split nuts 44 threadedly engage the threaded portion 26 of the shaft 14. It will be noted that the half nuts 44 engage the threaded portion 26. of the shaft 14 midway therealong so as to positively threadedly. engage the shaft 14v regardless of the fact that the half or split nuts 46 cannot threadedly engage the threaded portion 26 due to the length of reduced cross section 30. Upon rotation in the counterclockwise direction, the shaft 14 moves downwardly until the half orsplit nuts 44' are disposed in the lengths of reduced cross section 28. The lengths 28/ and 30 0f reduced cross section of the shaft 14 at each end of the threaded portion 26 limits axial movement of the shaft 14as the half nuts 44- and 46 disengage the threaded portion 26. by moving axially into lengths28-and 3:0 ofreduced cross section.

The, weights 66 on the. centrifugal members 48 and 50. cause the centrifugal members 48 and 50. to rotate in one of two opposite directions depending upon initial rotation of the. motor. When the motor is initially rotated the housing 32. rotates tending. to leave the weights 66 in position, i.e. rotation of the shaft or rotation of the housing- 32 precedes movement of the weights 66 thereby allowing, the weights 66 to move under centrifugal force further upwardly as the motor continues to rotate. Thus, initial rotation of the motor effects the lag in movement of the centrifugal members soas to determine. inwhich direction they move radially outwardly dueto centrifugal force.

The inventionhas been described in an illustrative manner, and it is toibe understood that the terminology which has. been used is intended: to be in the. nature of words of description rather thanof limitation.

Obviously, many modifications and variations of the present inventionare possible in light of the above teachings.

It is, therefore, to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

l. A linear actuator assembly comprising: an elongated threaded member, a rotated member rotatable about the axis of said threaded member, and at least one centrifugal member supported on said rotated member and moveable radially in response to rotation of said rotated member and including a first threaded nut portion for engaging said threaded member in response to rotation of said rotated member in one direction and a second threaded nut portion for engaging said threaded member in response to rotation of said rotated member in the opposite direction while said first threaded nut portion is disengaged from said threaded member.

2. A linear actuator assembly comprising: an axially moveable threaded member; a rotated member rotatable about the axis of said threaded member; and centrifugally actuated means movably supported on said rotated member for movement from a first engaged position in response to rotation in one direction through a disengaged position to a second engaged position in response to rotation in the opposite direction, said centrifugal'means including first thread means for engaging said threaded member in said first engaged position to move said threaded member axially in one direction and second thread means for engaging said threaded member in said second engaged position to move said threaded member in the opposite direction as said first thread means is disengaged from said threaded member.

3. An assembly as set forth in claim 2 wherein said threaded member comprises a shaft with a threaded portion, said shaft having a length of reduced cross section at each end of said threaded portion for limiting axial movement of said shaft as said first and second thread means disengage said threaded portion by moving axially into said lengths of reduced cross section.

4: An assembly as set forth in claim 3 wherein said first and second thread means are spaced from one another axially of said shaft so that when one of said thread means is positioned to be disposed in one of said lengths of reduced cross section the other thread means is positioned to engage said threaded portion.

5. An assembly as set forth in claim 2 wherein said threaded member comprises a shaft with a threaded portion and said centrifugal means includes at least one centrifugal member pivotally connected to said rotated member for pivotal movement about a pivotal axis which is transverse to said shaft.

6. An assembly as set forth in claim 5 wherein said first thread means includes a half nut supported by said centrifugal member axially of said shaft on one side of said pivotal axis and said second thread means includes a half nut supported by said centrifugal member axially of said shaft on the other side of said pivotal axis, each of said half nuts being spaced from said shaft when in said disengaged position.

7. An assembly as set forth in claim 6 wherein said centrifugal member includes a weight spaced axially along said shaft from said half nuts, said weight being disposed alongside said shaft and said rotated member when in said disengaged position.

8. An assembly as set forth in claim 7 wherein said centrifugal means includes a second centrifugal member pivotally connected to said rotated member for pivotal movement about said pivotal axis, said first thread means further including another half nut supported by said second centrifugal member and said second thread means further including another half nut supported by said second centrifugal member, said centrifugal members being substantially similar to and oppositely disposed with said second centrifugal member having a weight disposed on the opposite side of said shaft from the weight of the first mentioned centrifugal member whereby said half nuts of said first thread means engage opposite sides of said shaft in said first engaged position and said half nuts of said second thread means engage opposite sides of said shaft in said second engaged position.

9. An assembly as set forth in claim 8 wherein said shaft includes a length of reduced cross section at each end of said threaded portion for limiting axial movement of said shaft by said thread means as the half nuts thereof axially disengage said threaded portion by moving axially into said lengths of reduced cross section.

10. An assembly as set forth in claim 9 wherein the pair of half nuts of said first thread means are spaced axially along said shaft from the pair of said half nuts of said second thread means so that when one pair of half nuts are positioned to be disposed in one of said lengths of reduced cross section the other pair is positioned to engage said threaded portion, and vice versa.

11. An assembly as set forth in claim 10 including spring means reacting between said rotated member and said centrifugal members for biasing said centrifugal members to said disengaged positions.

12. An assembly as s et forth in claim 1 1 wherein said rotated member includes a housing for guiding axial movement of said shaft, said shaft being axially moveable when said centrifugal means is in said disengaged position. 

1. A linear actuator assembly comprising: an elongated threaded member, a rotated member rotatable about the axis of said threaded member, and at least one centrifugal member supported on said rotated member and moveable radially in response to rotation of said rotated member and including a first threaded nut portion for engaging said threaded member in response to rotation of said rotated member in one direction and a second threaded nut portion for engaging said threaded member in response to rotation of said rotated member in the opposite direction while said first threaded nut portion is disengaged from said threaded member.
 2. A linear actuator assembly comprising: an axially moveable threaded member; a rotated member rotatable about the axis of said threaded member; and centrifugally actuated means movably supported on said rotated member for movement from a first engaged position in response to rotation in one direction through a disengaged position to a second engaged position in response to rotation in the opposite direction, said centrifugal means including first thread means for engaging said threaded member in said first engageD position to move said threaded member axially in one direction and second thread means for engaging said threaded member in said second engaged position to move said threaded member in the opposite direction as said first thread means is disengaged from said threaded member.
 3. An assembly as set forth in claim 2 wherein said threaded member comprises a shaft with a threaded portion, said shaft having a length of reduced cross section at each end of said threaded portion for limiting axial movement of said shaft as said first and second thread means disengage said threaded portion by moving axially into said lengths of reduced cross section.
 4. An assembly as set forth in claim 3 wherein said first and second thread means are spaced from one another axially of said shaft so that when one of said thread means is positioned to be disposed in one of said lengths of reduced cross section the other thread means is positioned to engage said threaded portion.
 5. An assembly as set forth in claim 2 wherein said threaded member comprises a shaft with a threaded portion and said centrifugal means includes at least one centrifugal member pivotally connected to said rotated member for pivotal movement about a pivotal axis which is transverse to said shaft.
 6. An assembly as set forth in claim 5 wherein said first thread means includes a half nut supported by said centrifugal member axially of said shaft on one side of said pivotal axis and said second thread means includes a half nut supported by said centrifugal member axially of said shaft on the other side of said pivotal axis, each of said half nuts being spaced from said shaft when in said disengaged position.
 7. An assembly as set forth in claim 6 wherein said centrifugal member includes a weight spaced axially along said shaft from said half nuts, said weight being disposed alongside said shaft and said rotated member when in said disengaged position.
 8. An assembly as set forth in claim 7 wherein said centrifugal means includes a second centrifugal member pivotally connected to said rotated member for pivotal movement about said pivotal axis, said first thread means further including another half nut supported by said second centrifugal member and said second thread means further including another half nut supported by said second centrifugal member, said centrifugal members being substantially similar to and oppositely disposed with said second centrifugal member having a weight disposed on the opposite side of said shaft from the weight of the first mentioned centrifugal member whereby said half nuts of said first thread means engage opposite sides of said shaft in said first engaged position and said half nuts of said second thread means engage opposite sides of said shaft in said second engaged position.
 9. An assembly as set forth in claim 8 wherein said shaft includes a length of reduced cross section at each end of said threaded portion for limiting axial movement of said shaft by said thread means as the half nuts thereof axially disengage said threaded portion by moving axially into said lengths of reduced cross section.
 10. An assembly as set forth in claim 9 wherein the pair of half nuts of said first thread means are spaced axially along said shaft from the pair of said half nuts of said second thread means so that when one pair of half nuts are positioned to be disposed in one of said lengths of reduced cross section the other pair is positioned to engage said threaded portion, and vice versa.
 11. An assembly as set forth in claim 10 including spring means reacting between said rotated member and said centrifugal members for biasing said centrifugal members to said disengaged positions.
 12. An assembly as s et forth in claim 11 wherein said rotated member includes a housing for guiding axial movement of said shaft, said shaft being axially moveable when said centrifugal means is in said disengaged position. 